Violent crimes are committed every day in the United States by minors, between the ages of twelve and fifteen, and they are tried for these crimes in juvenile courts. Juveniles are prosecuted in juvenile court and receive a lesser sentence than an adult for violent crimes. Some people believe that teenagers should not be tried as adults but should only be tried as juveniles. Juveniles should be tried as adults, in adult court, when accused of murder, sexual offense and having previously been tried and convicted of two prior crimes. Before 1800 children over the age of seven were tried in adult court and upon conviction went to adult prison. In the nineteenth century it was believed that children lacked the mental capacity that comes with age and should be tested and rehabilitated separately from adults. In 1899, the first juvenile court was founded, in Chicago, with two basic principles. It was believed that minors could not be held responsible for their actions and could be rehabilitated. A "tough" approach has been adopted in many states, one example being California's Proposition 21, passed in 2000. (Juveniles) California's Proposition 21 states that prosecutors have the right to send "juveniles accused of crimes directly to adult court." (Juvenile) murder is not a school prank. Each jurisdiction in the United States has a different definition of homicide. A law enacted by the courts defines it as “the unlawful killing of a human being premeditated with malice”. (Murder) For a minor to be charged with murder it does not have to be planned or intentional; they may simply be accomplices. A minor, between the ages of twelve and fifteen, who commits an adult...... middle of paper ......ns Today 75.4 (2013): 60-64. Academic research completed. Network. April 18, 2014.Flesch, Lisa M. “Juvenile Crime and Why Waiver Is Not the Answer.” Family Court Review 42.3(2004):583-596. Academic research completed. Network. 18 April 2014. "Juvenile justice". Issues and controversies on file: n. page Problems and controversies. Archived Facts News Services, March 31, 2002. Web. April 21, 2014. "Juvenile Law." Gale Encyclopedia of American Law. Ed. Donna Batten. 3rd ed. "Aftercare." Encyclopedia of Juvenile Justice.Thousand Oaks, CA: Sage, 2003. 4. Print. "Murder." Gale Encyclopedia of American Law. 3rd ed. 151-155. Gale Virtual Reference Library. 2014.